update-index: fix worktree setup

diff --git a/diff.c b/diff.c
index bf5d5f15a3b54f1e1a0a2068990e899fd869d435..f70e6b4912911bd3f3a1d385fce7119a4a8107f6 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -1627,6 +1627,7 @@ static void builtin_checkdiff(const char *name_a, const char *name_b,
                xdemitcb_t ecb;
 
                memset(&xecfg, 0, sizeof(xecfg));
+               xecfg.ctxlen = 1; /* at least one context line */
                xpp.flags = XDF_NEED_MINIMAL;
                ecb.outf = xdiff_outf;
                ecb.priv = &data;